Maybe you should try building + installing everything with a different
--prefix (/usr/local or /opt/xorg_git or something like that). The wiki
page describes what you need to do, though not really in detail.

I currently am doing something a little more insane, but it happens to
work. The advantage is header and shared objects are not shared with
any other part of the system, this cuts down on problems caused by
these.

Using rbind and bind mounts I'm able to run a gnome session cross
chroots... gnome-panel plugins loaded from different chroots and the XC
server running in even another chroot.

To make things easy/ I'm using schroot, so my xserverrc and
xsessionrc files can enter the chroots.

It would be awsome to have a server chroot and client chroot, for
testing. Also bootable CDs, like knoppix would be nice.

I'm not sure what would go-into the chroots... would it make sence to
have the build environment and a script that grabs git, or just have
the binarys?

I think using chroots like this will make distributing and testing
software esier... for non-development systems there is an advantage to
using shared objects, but not for testing IMHO. Perhasps the answer
is to build a static Xserver instead? Still with that approch you
will want a controled chroot for your build process... So there may be
little extra bennifit.

I have done a completely fresh build after removing the stale headers
related to X in /usr/include. I used the prefix /opt/xorg_git and
downloaded the minimum needed to meet dependencies. The build completed
without error messages.

From the character-based console in Ubuntu's "recovery mode" I set
"LD_LIBRARY_PATH=/opt/xorg_git/lib" and then ran "startx --
/opt/xorg_git/bin/Xorg". I got a sensible display (xterm under fvwm as
specified in .xinitrc) but this display would not accept any input from
keyboard or mouse. I could, however, drop back to the character-based
console with Ctrl-F1 as usual.

The file /opt/xorg_git/var/log/Xorg.0.log showed no errors. In
particular, my weekend problem with opening /dev/dri/card0 seems to have
gone away.

I attach for your information:

(1) The shell script I used to carry out the latest build.
(2) Xorg.0.log
(3) xorg.conf

I'm a novice at this X business and appreciate all comments and advice.

#------------------------------------------------------------------
# For no good reason, just an experiment
#------------------------------------------------------------------
git clone git://anongit.freedesktop.org/git/xorg/driver/xf86-video-vesa
#------------------------------------------------------------------